1. Field of the Invention
The present invention relates to a method for repairing wells, including, but not necessarily limited to, oil and/or gas wells damaged by catastrophic events such as, for example, high winds or collisions with moving vessels. More particularly, the present invention relates to a method for installing pipe over damaged wells in order to reclaim said wells. More particularly still, the present invention relates to a method for aligning drive pipe that is to be driven over damaged wells during the reclamation and/or repair of such wells.
2. Description of the Related Art
In many cases, especially in offshore operations, large diameter pipe, (commonly referred to as drive pipe or conductor pipe), is driven into the surface of the earth as one of the initial steps of the well-drilling process. Such drive pipe, which can be driven as deep as several hundred feet into the earth, provides structural integrity for the ongoing drilling process in unconsolidated formations near the earth's surface.
Tubular drive pipe having an internal bore is typically driven into the surface of the earth using a large hammer or similar equipment that acts in much the same way as a pile driver. Such hammers are used to strike the upper surface of the drive pipe in a downward direction, thereby forcing the drive pipe axially into the earth's crust. With each blow of the hammer, the drive pipe advances deeper into the earth's crust until penetration stops, or until a predetermined depth is achieved.
After drive pipe has been driven to a desired depth, a well is typically drilled deeper using conventional drilling methods. Specifically, a drill bit (having an outer diameter smaller than the internal diameter of the drive pipe) is conveyed into the internal bore of the drive pipe on drill pipe or other similar tubular workstring using a drilling rig situated over the drive pipe. A section of hole is then drilled deeper into the earth's crust through the internal bore of the drive pipe and out the bottom of the drive pipe. Once a section of hole has been drilled to a desired depth, a smaller string of pipe known as casing (having an outer diameter smaller than the internal diameter of the drive pipe) is then typically conveyed into the well and cemented in place. Such casing is often installed to provide structural integrity to the well-bore and keep geologic formations isolated from one another.
After a well has been drilled to its desired depth, production tubing and other equipment can be installed in said well. Additionally, surface valves and related equipment, commonly referred to as a “Christmas tree”, can be installed on the upper portion of such well. In marine environments, such as offshore or in inland waters, it is often desirable to have access to the Christmas tree and related equipment on a well. For this reason, wells are typically designed so that a Christmas tree (and some length of drive pipe, casing and tubing) is situated above the surface of the water. In such cases, the drive pipe, casing and tubing extend vertically out of the mud-line (that is, the interface between the earth's crust and the water) for some distance. In many cases, the upper portions of such wells are also attached to support structures, such as platforms and the like, which are in turn anchored to the earth's crust.
When a major weather phenomenon or other similar event occurs (such as, for example, a hurricane or severe windstorm) in a marine environment, wells can be severely damaged. Often, such wells get “pushed over”—that is, the wells can bend at or near the mud-line. In such cases, the Christmas trees and other equipment at the upper extent of the wells can frequently lose their vertical orientation. In extreme cases, the Christmas trees can actually be pushed under the surface of the water. Similarly, boats or other vessels can collide with such wells, thereby knocking over the wells. When this occurs, the damaged wells are effectively useless; the wells must be repaired before any production can be achieved from such wells or significant remedial work can be performed on the wells.
Accordingly, it is an object of the present invention to provide a means for repairing and reclaiming wells that have been damaged by severe weather, collision or other catastrophic event.